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Perspex cylinderhead

Posted: Sun Apr 22, 2018 11:24 am
by RobThomas
https://www.youtube.com/watch?v=icoBqTEZbbw

6 minutes in. Interesting video.

Re: Perspex cylinderhead

Posted: Sun Apr 22, 2018 9:17 pm
by Mark Wilson
The whole film is fascinating, thanks for posting it.

Mark

Re: Perspex cylinderhead

Posted: Sun Apr 22, 2018 9:56 pm
by alanworland
Great bit of film especially the fish tank test on the windscreen!

Alan

Re: Perspex cylinderhead

Posted: Tue Apr 24, 2018 9:39 am
by myoldjalopy
Perspex cylinder head - good for checking TDC! 8)

Re: Perspex cylinderhead

Posted: Tue Apr 24, 2018 10:41 am
by oliver90owner
myoldjalopy wrote: Tue Apr 24, 2018 9:39 am Perspex cylinder head - good for checking TDC! 8)
Might be for some, but not really close enough for me! :D screwdriver through the spark plug hole might be as good and a lot easier. :D

Re: Perspex cylinderhead

Posted: Tue Apr 24, 2018 12:24 pm
by philthehill
A screw driver through the spark plug hole will still be not good enough.
There is a lot of crankshaft movement in degrees either side of TDC with the piston crown appearing to stay stationary at assumed TDC.

Re: Perspex cylinderhead

Posted: Tue Apr 24, 2018 2:46 pm
by oliver90owner
I quite agree. Which is why I indicated that a screwdriver was possibly no better. If I want TDC accurately, it is finding a known position on the up and down strokes with a dial gauge and halving the found distance, between the two markings made on the flywheel circumference.

The same principle applies to timing pendulum oscillations - one always times from the point of maximum velocity, not the less determinate point of change of direction (zero velocity in each of the two directions of travel).

RAB

Re: Perspex cylinderhead

Posted: Tue Apr 24, 2018 6:36 pm
by les
I agree, a screwdriver is not accurate and can only be considered an indication. I read the comment about the Perspex head and TDC, as just a light hearted observation, not to be taken too seriously! :o

Re: Perspex cylinderhead

Posted: Tue Apr 24, 2018 7:38 pm
by myoldjalopy
You are absolutely correct, Les It was, indeed, meant as a light hearted comment, if not an outright leg-pull!

Re: Perspex cylinderhead

Posted: Tue Apr 24, 2018 10:58 pm
by oliver90owner
Correct! :D

That’s why there was a load of smileys plastered around (for those that don't notice these things). :D

Re: Perspex cylinderhead

Posted: Tue Apr 24, 2018 11:19 pm
by les
We believe you--- thousands wouldn't. :D